Devices such as steam mops and handheld steamers are configured for cleaning a wide variety of common household surfaces such as bare flooring, including tile, hardwood, laminate, vinyl, and linoleum, as well as countertops, stove tops and the like. Typically, steam mops comprise at least one tank or reservoir for storing liquid that is fluidly connected to a selectively engageable pump or valve. The outlet of the pump or valve is fluidly connected to a steam generator, which comprises a heating element for heating the liquid. The steam generator produces steam, which can be directed towards the surface to be cleaned through a distributor nozzle or a manifold located in a foot or cleaning head that engages the surface to be cleaned. Steam is typically applied to the backside of a cleaning pad that is removably attached to the cleaning head. Steam eventually saturates the cleaning pad and the damp pad is wiped across the surface to be cleaned to remove dirt, dust, and debris present on the surface, thereby collecting and absorbing soil and soiled cleaning composition into the pad. Additionally, auxiliary compositions, such as fragrances, detergents or other additives can be supplied via the liquid tank for distribution through the surface cleaning apparatus to improve cleaning efficacy or to provide other sensory benefits. Alternatively, these auxiliary compositions can be impregnated, embedded, encapsulated within, or otherwise affixed to the cleaning pad. Steam from the steam distributor nozzle can release the composition onto the surface to be cleaned.
Some steam appliances locate a removable water supply tank and a steam generating device on an upright handle and deliver steam through a universal joint to a pivoting cleaning foot that is typically covered by a reusable cleaning pad. One example is the BISSELL Steam Mop™ Deluxe (Model 31N1). Details of a similar steam mop device are disclosed in Chinese Patent No. CN2482956 to Wu, issued Mar. 27, 2002. In an alternate configuration, the steam generator can be located on the cleaning head as disclosed in U.S. Pat. No. 6,584,990 to Shaw, issued Jul. 1, 2003.
Pre-moistened, impregnated cleaning pads and cleaning pads that can also reabsorb liquid from a surface to be cleaned are disclosed in U.S. Pat. No. 7,144,173 to Policicchio, issued Dec. 5, 2006.
The cleaning effectiveness of the cleaning pad depends on the soil level of the cleaning pad and the presence of any auxiliary compositions which may be incorporated into the pad. During use, as the cleaning pad attracts and absorbs larger amounts of soil over time, the cleaning effectiveness can diminish. Additionally, cleaning performance of the pad can also diminish when auxiliary compositions incorporated in the pad are expended. Therefore, to maintain optimal cleaning performance, a user must frequently ascertain the condition of the cleaning pad, which generally requires manually rotating the foot of the steam mop so the user can view the cleaning pad, which is mounted to the bottom of the foot. This is a cumbersome and user-dependent operation, which does not provide sufficient visual feedback to the user in order to make accurate judgments regarding the condition of the cleaning pad.